Answer:
<u><em>Steven is 15 and one half years old now</em></u>
Step-by-step explanation:
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Linear equations
Sometimes we need to know the value of a variable in a given equation and that variable is given as a polynomial of degree 1. Solving for that variable means isolating it and replacing the other known values
Steven was 7 years old eight and one-half years ago. If we call x as the actual age of Steven, his age eight and one-half years ago was

We know he was 7 years old then, so

We need to know his actual age, so let's solve for x, adding
to each side of the equation

Simplifying

Steven is 15 and one half years old now